1. Field of the Invention
This invention relates to ironmaking by means of a smelting shaft furnace, such shaft furnaces being typified by the modern blast furnace where a charge of coke, ore (usually including a proportion of sinter and perhaps pelletised material), and various additives is inserted in the top of the furnace, and the necessary combustion and smelting if affected in the furnace by means of hot air blasts injected into the furnace via tuyeres from the Bustle pipe in the Bosh zone of the furnace. The product of such furnaces is iron which is tapped from the hearth adjacent the base of the furnace.
2. Description of the prior art
It has previously been proposed, with blast furnaces, to introduce into the blast at the tuyeres, fuel oil or other hydrocarbon fuel to enrich and augment the thermal input and hence reduce the coke requirement of the furnace. Again it has been proposed to use coal, in granular form or powder form, or in the form of a powder or slurry in water as such fuel. It has similarly been proposed to introduce modest levels of oxygen enrichment of the hot blast to enhance the smelting capability of the furnace. All of these proposals, however, are only intended to augment and improve the standard operation of the blast furnace. The blast furnace operation with such augmentation continues to be operated in normal manner, albeit hopefully with greater efficiency in production and/or economics.